Pages

Wednesday, September 30, 2009

Firing Room 1: Adding One More "First"

If rooms could boast about an illustrious past, then the Launch Control Center's Firing Room 1 at NASA's Kennedy Space Center in Florida would have ample reason. Soon another chapter of launch history will be written from there as the Ares I-X launch team assembles in the newly remodeled nerve center for the rocket's flight test.

Firing Room 1 "Firsts"

Saturn V
Saturn V with crew
Moon mission with crew
Space Shuttle

A gathering on Sept. 25 honored the history and marked the firing room's new mission as the Constellation Program officially took possession of the facility.

Image above: With the Ares rocket models in the background, Bob Crippen addressed the crowd assembled in the remodeled Firing Room 1. Image credit: NASA/Kim Shiflett

Among those with special ties to the firing room was astronaut Bob Crippen, who, along with John Young, flew the first space shuttle mission. The firing room was used for that launch and named in their honor a few years ago.

"I expect nothing but success from this firing room in the future," said Crippen. "Getting ready to launch the Ares out of this firing room is an important event. The future of human spaceflight is dependent on it, in my opinion."

He concluded, "We're going to have hundreds of launches right out of this control room that John and I are very proud to have our names on."

Bob Cabana, Kennedy's director and veteran shuttle astronaut, explained that the new design of the firing room allows it to be configured for whatever the future launch needs might be.

"It's great to be here because this is our future," said Cabana. "We're going to be launching rockets, we're going to be exploring beyond low Earth orbit, we're going to be sending humans and payloads to space, and it's going to happen from this firing room."

Image above: Kennedy Space Center Director Bob Cabana talks about the new mission of the firing room. Behind him are the new work consoles that will be used by the launch team. Image credit: NASA/Kim Shiflett

Constellation Program Manager Jeff Hanley explained that the room already is serving the program, being used the previous week for an Ares I-X launch simulation, as well as for powered testing of the actual rocket.

"I'm so proud of the team that has continued to go forward with our plan," Hanley said. "This room is evidence of that. The rocket that is stacked in High Bay 3 is evidence of that."

Follow the Ares I-X flight test.

Cheryl L. Mansfield
NASA's John F. Kennedy Space Center

For more information visit http://www.nasa.gov/mission_pages/constellation/ares/flighttests/aresIx/firing_room_one.html

Cosmic Rays Hit Space Age High

Planning a trip to Mars? Take plenty of shielding. According to sensors on NASA's ACE (Advanced Composition Explorer) spacecraft, galactic cosmic rays have just hit a Space Age high.

"In 2009, cosmic ray intensities have increased 19% beyond anything we've seen in the past 50 years," says Richard Mewaldt of Caltech. "The increase is significant, and it could mean we need to re-think how much radiation shielding astronauts take with them on deep-space missions."

Energetic iron nuclei counted by the Cosmic Ray Isotope Spectrometer on NASA's Advanced Composition Explorer (ACE) spacecraft reveal that cosmic ray levels have jumped 19% above the previous Space Age high. Credit: Richard Mewaldt/Caltech

The cause of the surge is solar minimum, a deep lull in solar activity that began around 2007 and continues today. Researchers have long known that cosmic rays go up when solar activity goes down. Right now solar activity is as weak as it has been in modern times, setting the stage for what Mewaldt calls "a perfect storm of cosmic rays."

"We're experiencing the deepest solar minimum in nearly a century," says Dean Pesnell of the Goddard Space Flight Center, "so it is no surprise that cosmic rays are at record levels for the Space Age."

An artist's concept of the heliosphere, a magnetic bubble that partially protects the solar system from cosmic rays. Credit: Richard Mewaldt/Caltech

Galactic cosmic rays come from outside the solar system. They are subatomic particles--mainly protons but also some heavy nuclei--accelerated to almost light speed by distant supernova explosions. Cosmic rays cause "air showers" of secondary particles when they hit Earth's atmosphere; they pose a health hazard to astronauts; and a single cosmic ray can disable a satellite if it hits an unlucky integrated circuit.

The sun's magnetic field is our first line of defense against these highly-charged, energetic particles. The entire solar system from Mercury to Pluto and beyond is surrounded by a bubble of solar magnetism called "the heliosphere." It springs from the sun's inner magnetic dynamo and is inflated to gargantuan proportions by the solar wind. When a cosmic ray tries to enter the solar system, it must fight through the heliosphere's outer layers; and if it makes it inside, there is a thicket of magnetic fields waiting to scatter and deflect the intruder.

"At times of low solar activity, this natural shielding is weakened, and more cosmic rays are able to reach the inner solar system," explains Pesnell.

The heliospheric current sheet is shaped like a ballerina's skirt. Credit: J. R. Jokipii, University of Arizona

Mewaldt lists three aspects of the current solar minimum that are combining to create the perfect storm:

1. The sun's magnetic field is weak. "There has been a sharp decline in the sun's interplanetary magnetic field (IMF) down to only 4 nanoTesla (nT) from typical values of 6 to 8 nT," he says. "This record-low IMF undoubtedly contributes to the record-high cosmic ray fluxes."

2. 2. The solar wind is flagging. "Measurements by the Ulysses spacecraft show that solar wind pressure is at a 50-year low," he continues, "so the magnetic bubble that protects the solar system is not being inflated as much as usual." A smaller bubble gives cosmic rays a shorter-shot into the solar system. Once a cosmic ray enters the solar system, it must "swim upstream" against the solar wind. Solar wind speeds have dropped to very low levels in 2008 and 2009, making it easier than usual for a cosmic ray to proceed.

3. The current sheet is flattening. Imagine the sun wearing a ballerina's skirt as wide as the entire solar system with an electrical current flowing along the wavy folds. That is the "heliospheric current sheet," a vast transition zone where the polarity of the sun's magnetic field changes from plus (north) to minus (south). The current sheet is important because cosmic rays tend to be guided by its folds. Lately, the current sheet has been flattening itself out, allowing cosmic rays more direct access to the inner solar system.


"If the flattening continues as it has in previous solar minima, we could see cosmic ray fluxes jump all the way to 30% above previous Space Age highs," predicts Mewaldt.

Earth is in no great peril from the extra cosmic rays. The planet's atmosphere and magnetic field combine to form a formidable shield against space radiation, protecting humans on the surface. Indeed, we've weathered storms much worse than this. Hundreds of years ago, cosmic ray fluxes were at least 200% higher than they are now. Researchers know this because when cosmic rays hit the atmosphere, they produce an isotope of beryllium, 10Be, which is preserved in polar ice. By examining ice cores, it is possible to estimate cosmic ray fluxes more than a thousand years into the past. Even with the recent surge, cosmic rays today are much weaker than they have been at times in the past millennium.

"The space era has so far experienced a time of relatively low cosmic ray activity," says Mewaldt. "We may now be returning to levels typical of past centuries."

NASA spacecraft will continue to monitor the situation as solar minimum unfolds. Stay tuned for updates.

Dr. Tony Phillips
Heliophysics News Team

For more information visit http://www.nasa.gov/topics/solarsystem/features/ray_surge.html

NASA Spacecraft Sees Ice on Mars Exposed by Meteor Impacts

PASADENA, Calif. -- NASA's Mars Reconnaissance Orbiter has revealed frozen water hiding just below the surface of mid-latitude Mars. The spacecraft's observations were obtained from orbit after meteorites excavated fresh craters on the Red Planet.

Scientists controlling instruments on the orbiter found bright ice exposed at five Martian sites with new craters that range in depth from approximately half a meter to 2.5 meters (1.5 feet to 8 feet). The craters did not exist in earlier images of the same sites. Some of the craters show a thin layer of bright ice atop darker underlying material. The bright patches darkened in the weeks following initial observations, as the freshly exposed ice vaporized into the thin Martian atmosphere. One of the new craters had a bright patch of material large enough for one of the orbiter's instruments to confirm it is water-ice.

The finds indicate water-ice occurs beneath Mars' surface halfway between the north pole and the equator, a lower latitude than expected in the Martian climate.

"This ice is a relic of a more humid climate from perhaps just several thousand years ago," said Shane Byrne of the University of Arizona, Tucson.

Byrne is a member of the team operating the orbiter's High Resolution Imaging Science Experiment, or HiRISE camera, which captured the unprecedented images. Byrne and 17 co-authors report the findings in the Sept. 25 edition of the journal Science.

"We now know we can use new impact sites as probes to look for ice in the shallow subsurface," said Megan Kennedy of Malin Space Science Systems in San Diego, a co-author of the paper and member of the team operating the orbiter's Context Camera.

The High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter took these images of a fresh, 6-meter-wide (20-foot-wide) crater on Mars on Oct. 18, 2008, (left) and on Jan. 14, 2009. Each image is 35 meters (115 feet) across. Image Credit: NASA/JPL-Caltech/University of Arizona

During a typical week, the Context Camera returns more than 200 images of Mars that cover a total area greater than California. The camera team examines each image, sometimes finding dark spots that fresh, small craters make in terrain covered with dust. Checking earlier photos of the same areas can confirm a feature is new. The team has found more than 100 fresh impact sites, mostly closer to the equator than the ones that revealed ice.

An image from the camera on Aug. 10, 2008, showed apparent cratering that occurred after an image of the same ground was taken 67 days earlier. The opportunity to study such a fresh impact site prompted a look by the orbiter's higher resolution camera on Sept. 12, 2008, confirming a cluster of small craters.

"Something unusual jumped out," Byrne said. "We observed bright material at the bottoms of the craters with a very distinct color. It looked a lot like ice."

The bright material at that site did not cover enough area for a spectrometer instrument on the orbiter to determine its composition. However, a Sept. 18, 2008, image of a different mid-latitude site showed a crater that had not existed eight months earlier. This crater had a larger area of bright material.

"We were excited about it, so we did a quick-turnaround observation," said co-author Kim Seelos of Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Everyone thought it was water-ice, but it was important to get the spectrum for confirmation."

Mars Reconnaissance Orbiter Project Scientist Rich Zurek, of NASA's Jet Propulsion Laboratory, Pasadena, Calif., said, "This mission is designed to facilitate coordination and quick response by the science teams. That makes it possible to detect and understand rapidly changing features."

The ice exposed by fresh impacts suggests that NASA's Viking Lander 2, digging into mid-latitude Mars in 1976, might have struck ice if it had dug 10 centimeters (4 inches) deeper. The Viking 2 mission, which consisted of an orbiter and a lander, launched in September 1975 and became one of the first two space probes to land successfully on the Martian surface. The Viking 1 and 2 landers characterized the structure and composition of the atmosphere and surface. They also conducted on-the-spot biological tests for life on another planet.

NASA's Jet Propulsion Laboratory in Pasadena manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft. The Context Camera was built and is operated by Malin Space Science Systems. The University of Arizona operates the HiRISE camera, which Ball Aerospace & Technologies Corp., in Boulder, Colo., built. The Johns Hopkins University Applied Physics Laboratory led the effort to build the Compact Reconnaissance Imaging Spectrometer and operates it in coordination with an international team of researchers.

To view images of the craters and learn more about the Mars Reconnaissance Orbiter, http://www.nasa.gov/mro or http://marsprogram.jpl.nasa.gov/mro/

Media contacts: Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.govDwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

For more information visit http://www.nasa.gov/mission_pages/MRO/news/mro-20090924r.html

NASA's Spitzer Spots Clump Of Swirling Planetary Material

PASADENA, Calif. -- Astronomers have witnessed odd behavior around a young star. Something, perhaps another star or a planet, appears to be pushing a clump of planet-forming material around. The observations, made with NASA's Spitzer Space Telescope, offer a rare look into the early stages of planet formation.

Planets form out of swirling disks of gas and dust. Spitzer observed infrared light coming from one such disk around a young star, called LRLL 31, over a period of five months. To the astronomers' surprise, the light varied in unexpected ways, and in as little time as one week. Planets take millions of years to form, so it's rare to see anything change on time scales we humans can perceive.

One possible explanation is that a close companion to the star - either a star or a developing planet - could be shoving planet-forming material together, causing its thickness to vary as it spins around the star.

"We don't know if planets have formed, or will form, but we are gaining a better understanding of the properties and dynamics of the fine dust that could either become, or indirectly shape, a planet," said James Muzerolle of the Space Telescope Science Institute, Baltimore, Md. Muzerolle is first author of a paper accepted for publication in the Astrophysical Journal Letters. "This is a unique, real-time glimpse into the lengthy process of building planets."

Astronomers using NASA's Spitzer Space Telescope found evidence that a companion to a star -- either another star or a planet -- could be pushing planetary material together, as illustrated here.

One theory of planet formation suggests that planets start out as dusty grains swirling around a star in a disk. They slowly bulk up in size, collecting more and more mass like sticky snow. As the planets get bigger and bigger, they carve out gaps in the dust, until a so-called transitional disk takes shape with a large doughnut-like hole at its center. Over time, this disk fades and a new type of disk emerges, made up of debris from collisions between planets, asteroids and comets. Ultimately, a more settled, mature solar system like our own forms.

Before Spitzer was launched in 2003, only a few transitional disks with gaps or holes were known. With Spitzer's improved infrared vision, dozens have now been found. The space telescope sensed the warm glow of the disks and indirectly mapped out their structures.

Muzerolle and his team set out to study a family of young stars, many with known transitional disks. The stars are about two to three million years old and about 1,000 light-years away, in the IC 348 star-forming region of the constellation Perseus. A few of the stars showed surprising hints of variations. The astronomers followed up on one, LRLL 31, studying the star over five months with all three of Spitzer's instruments.

The observations showed that light from the inner region of the star's disk changes every few weeks, and, in one instance, in only one week. "Transition disks are rare enough, so to see one with this type of variability is really exciting," said co-author Kevin Flaherty of the University of Arizona, Tucson.

Both the intensity and the wavelength of infrared light varied over time. For instance, when the amount of light seen at shorter wavelengths went up, the brightness at longer wavelengths went down, and vice versa.

Muzerolle and his team say that a companion to the star, circling in a gap in the system's disk, could explain the data. "A companion in the gap of an almost edge-on disk would periodically change the height of the inner disk rim as it circles around the star: a higher rim would emit more light at shorter wavelengths because it is larger and hot, but at the same time, the high rim would shadow the cool material of the outer disk, causing a decrease in the longer-wavelength light. A low rim would do the opposite. This is exactly what we observe in our data," said Elise Furlan, a co-author from NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The companion would have to be close in order to move the material around so fast -- about one-tenth the distance between Earth and the sun.

The astronomers plan to follow up with ground-based telescopes to see if a companion is tugging on the star hard enough to be perceived. Spitzer will also observe the system again in its "warm" mission to see if the changes are periodic, as would be expected with an orbiting companion. Spitzer ran out of coolant in May of this year, and is now operating at a slightly warmer temperature with two infrared channels still functioning.

"For astronomers, watching anything in real-time is exciting," said Muzerolle. "It's like we're biologists getting to watch cells grow in a petri dish, only our specimen is light-years away."

Other authors are Zoltan Balog, Max Planck Institute for Astronomy, Germany; Paul S. Smith and George Rieke, University of Arizona; Lori Allen, National Optical Astronomy Observatory, Tucson; Nuria Calvet, University of Michigan, Ann Arbor; Paola D'Alessio, National Autonomous University of Mexico; S. Thomas Megeath, University of Toledo, Ohio; August Muench, Harvard-Smithsonian Center for Astrophysics, Cambridge; William H. Sherry, National Solar Observatory, Tucson.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://www.spitzer.caltech.edu/spitzer and http://www.nasa.gov/spitzer .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

For more information visit http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20090923.html

NASA's LCROSS Mission Changes Impact Crater

MOFFETT FIELD, Calif. -- NASA's Lunar Crater Observation and Sensing Satellite mission (LCROSS) based on new analysis of available lunar data, has shifted the target crater from Cabeus A to Cabeus (proper).

The decision was based on continued evaluation of all available data and consultation/input from members of the LCROSS Science Team and the scientific community, including impact experts, ground and space based observers, and observations from Lunar Reconnaissance Orbiter (LRO), Lunar Prospector (LP), Chandrayaan-1 and JAXA's Kaguya spacecraft. This decision was prompted by the current best understanding of hydrogen concentrations in the Cabeus region, including cross-correlation between the latest LRO results and LP data sets.

The general consensus of lunar experts led by the LCROSS science team is that Cabeus shows, with the greatest level of certainty, the highest hydrogen concentrations at the south pole. Further consideration of the most current terrain models provided by JAXA's Kaguya spacecraft and the LRO Lunar Orbiter Laser Altimeter (LOLA) was important in the decision process.The models show a small valley in an otherwise tall Cabeus perimeter ridge, which will allow for sunlight to illuminate the ejecta cloud on Oct. 9, and much sooner than previously estimated for Cabeus. While the ejecta does have to fly to higher elevations to be observed by Earth assets, a shadow cast by a large hill along the Cabeus ridge, provides an excellent, high-contrast, back drop for ejecta and vapor measurements.

The LCROSS team concluded that Cabeus provided the best chance for meeting its mission goals. The team critically assessed and successfully advocated for the change with the Lunar Precursor Robotic Program (LPRP) office. The change in impact crater was factored into LCROSS' most recent Trajectory Correction Maneuver, TCM7.

During the last days of the mission, the LCROSS team will continue to refine the exact point of impact within Cabeus crater to avoid rough spots, and to maximize solar illumination of the debris plume and Earth observations.





The Near Infrared (0.9-1.7 mm) Camera #2 image of Earth as part of a LCROSS payload calibration activity on Sept. 18, 2009. At the time of this image, the LCROSS spacecraft was nominally 348,000 miles (559,400 km) from Earth. The inset shows the Earth face as seen by the LCROSS spacecraft. The Earth’s north pole is indicated by the arrow. The image on right shows water vapor as seen by GOES at a similar time as the LCROSS observation. The red letters indicate potential weather features common in both images. Credit: NASA Ames


Shown here is the slightly greater than quarter-Earth, sized ~1.5 deg along its diameter, in four colors. The false color (where red is warm, blue is cold) mid-infrared images reveal warmer summer mid-Atlantic temperatures about the equator and Northern Hemisphere. The images also reveal the whole Earth’s disk. South America is to the left. Africa is to the right. Antarctica is at the bottom. All instruments performed well during the calibration. Credit: NASA Ames

For more information visit http://www.nasa.gov/mission_pages/LCROSS/main/index.html

MESSENGER Spacecraft Prepares for Final Pass by Mercury

NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging spacecraft known as MESSENGER will fly by Mercury for the third and final time on Sept. 29. The spacecraft will pass less than 142 miles above the planet's rocky surface for a final gravity assist that will enable it to enter Mercury's orbit in 2011.

Determining the composition of Mercury's surface is a major goal of the orbital phase of the mission. The spacecraft already has imaged more than 90 percent of the planet's surface. The spacecraft's team will activate instruments during this flyby to view specific features to uncover more information about the planet.

"This flyby will be our last close look at the equatorial regions of Mercury, and it is our final planetary gravity assist, so it is important for the entire encounter to be executed as planned," said Sean Solomon, principal investigator at the Carnegie Institution in Washington. "As enticing as these flybys have been for discovering some of Mercury's secrets, they are the hors d'oeuvres to the mission's main course -- observing Mercury from orbit for an entire year.

Messenger at Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

The spacecraft may observe how the planet interacts with conditions in interplanetary space as a result of activity on the sun. During this encounter, high spectral- and high spatial-resolution measurements will be taken again of Mercury's tenuous atmosphere and tail.

"Scans of the planet's comet-like tail will provide important clues regarding the processes that maintain the atmosphere and tail," said Noam Izenberg, the instrument's scientist at the Johns Hopkins University Applied Physics Laboratory, or APL, in Laurel, Md. "The Mercury Atmospheric and Surface Composition Spectrometer will give us a snapshot of how the distribution of sodium and calcium vary with solar and planetary conditions. In addition, we will target the north and south polar regions for detailed observations and look for several new atmospheric constituents."

As the spacecraft approaches Mercury, cameras will photograph previously unseen terrain. As the spacecraft departs, it will take high-resolution images of the southern hemisphere. Scientists expect the spacecraft's imaging system to take more than 1,500 pictures. Those images will be used to create a mosaic to complement the high resolution, northern-hemisphere mosaic obtained during the second Mercury flyby. The first flyby took the spacecraft over the eastern hemisphere in January 2008, and the second flyby took it over western side in October 2008.

"We are going to collect high resolution, color images of scientifically interesting targets that we identified from the second flyby," said Ralph McNutt, a project scientist at APL. "The spectrometer also will make measurements of those targets at the same time."

Two spacecraft maneuvers will improve the ability of the spacecraft's Neutron Spectrometer to detect low-energy neutrons sensitive to the abundances of iron and titanium on Mercury's surface. These two elements absorb neutrons and are critical to an understanding of how the planet and its crust formed. A combination of day and night measurements will enable scientists to test the influence that planetary surface temperature has on the neutron population. The data are important for interpreting measurements that will be made after the probe is in orbit around Mercury.

An altimeter will make a topographic profile along the instrument ground track of Mercury's surface. The data gathered will provide additional topography of Mercury's surface features for ongoing studies of the form and structure of its craters and large faults. The information also will extend scientists' equatorial view of Mercury's global shape and allow them to confirm the discovery made during the first and second flyby that Mercury's equatorial region is slightly elliptical.

The spacecraft has completed nearly three-quarters of its 4.9-billion-mile journey to enter orbit around Mercury. The trip includes more than 15 trips around the sun. In addition to flying by Mercury, the spacecraft flew past Earth in August 2005 and Venus in October 2006 and June 2007.

The project is the seventh in NASA's Discovery Program of low-cost, scientifically focused space missions. The spacecraft was designed and built by APL. The mission also is managed and operated by APL for NASA's Science Mission Directorate in Washington.

For more information about the mission, visit:

› NASA's MESSENGER Mission Page
› Information and briefing materials on MESSENGER's third flyby

Messenger team
NASA Headquarters/Johns Hopkins Applied Physics Lab

For more information visit http://www.nasa.gov/mission_pages/messenger/media/final_pass.html

Wednesday, September 23, 2009

With an Eye on Locusts and Vegetation, Scientists Make a Good Tool Better

Locusts, the grasshopper-like insects of Biblical lore, are normally docile creatures that prefer solitary lives in the desert, away from other members of their species. But sometimes, when the rains come and patches of green begin to dot dry landscapes, their populations skyrocket and something extraordinary can happen. Hormonal changes, triggered by crowding, can cause the insects to change color, become more active and congregate in huge swarms capable of decimating crops.

In the 1980s, scientists at NASA's Goddard Space Flight Center and the United Nations' Food and Agriculture Organization (FAO) teamed up to develop a monitoring system that used satellite observations and other environmental data to monitor vegetation in the deserts of Africa, the Middle East and Asia for signs that swarms may be imminent. The Desert Locust Information Service (DLIS) used the satellite-derived Normalized Difference Vegetation Index (NDVI) -- based on the ratio of red and infrared radiation reflecting off the leaves of plants -- to detect where deserts were greening the most.

Environmental conditions can cause desert locusts to enter a "gregarious" phase in which they change colors, become more active, and congregate in large swarms. Credit: NASA Earth Observatory

Compared to previous attempts to study vegetation from space, NDVI represented a vast improvement. Scientists could determine whether plant growth was significantly more or less productive than usual over a given time period - just what they needed to predict whether locusts were likely to swarm. The advance gave officials precious time to target worrisome locust populations with pesticides before they could swarm and take their toll on crops.

Ironing Out the Wrinkles

Though state-of-the-art at the time, the system had a few shortcomings. For instance, bare soil in deserts can register an NDVI value similar to that of sparse vegetation. As a result, DLIS has occasionally issued false alarms, interpreting vegetation growth where there was none and missing the development of some real vegetation.

"If DLIS warns locust control teams of a risk and then it doesn't materialize, or if it misses places where vegetation and swarms may be developing, then officials could be less apt to mobilize the next time," said Pietro Ceccato, an associate research scientist at Columbia University, N.Y., who has also worked with the FAO on its locust monitoring system.

Swarms typically contain between 40 and 80 million locusts per square kilometer. This swarm passed through Nouakchott, the largest city in Mauritania. Credit: Food and Agriculture Organization of the United Nations

That system has evolved over the years, particularly since the arrival of the MODIS instruments on NASA's Terra and Aqua satellites, which offer a considerably better view than previous instruments. Since 2002, locust monitors at DLIS have supplemented NDVI with information from an additional channel - the shortwave infrared -- to create composite images that better account for the differences between vegetation and bare soil.

While NDVI remains the most important tool available to monitor locusts from space, remote sensing specialists are hardly resting on their NDVI laurels. For instance, the Goddard group that helped create NDVI and FAO’s locust monitoring system continues to refine its ability to screen out extraneous data and increase image resolution.

Beyond Locusts

During quiet periods, known as recessions, desert locusts live within the semi-arid and arid areas of Northern Africa. However, as shown in yellow, desert locusts can spread over a much larger area during swarms. Credit: NASA Earth Observatory

The impulse to refine NDVI isn't limited to locust studies. Small particles in the atmosphere (aerosols) and water vapor can make interpreting NDVI measurements difficult in some situations, explained Susan Ustin, a remote sensing expert at the University of California-Davis. Clouds, especially thin cirrus clouds, also can contaminate short-term measurements. And the color of soil can cause complications because vegetation over dark soils produces higher NDVI values than the same amount of vegetation over light soils.

As technology has advanced, scientists have attempted to overcome such problems by developing dozens of experimental indices, many of which are based upon NDVI. "It seems like a new index comes out every month," said Ustin. In fact, there are so many new indices being developed for such a variety of situations that's it's sometimes difficult for researchers to agree on which are worth pursuing.

Another problem with all the new indices, said Compton Tucker, a scientist at NASA Goddard who pioneered the use of NDVI, is that many are geared toward such specific ecosystems and environments that they aren't useful globally. There's a risk of creating niche products that won’t allow researchers to see the bigger, global picture.

Swarms are not visible from space, but the vegetation that they depend upon is readily detectable. In green, this NDVI-based map shows areas with especially lush vegetation, which serve as fertile breeding grounds for locusts. Credit: NASA Earth Observatory

"Most of the new indices will never make it out of the lab," said Steve Running, a vegetation scientist at the University of Montana and member of the Intergovernmental Panel on Climate Change. "But I think that we'll eventually come up with one or two alternatives that we can use to complement NDVI."

Related Links:


› NDVI: Satellites Could Help Keep Hungry Populations Fed as Climate Changes
› Measuring Vegetation (NDVI & EVI)
› An Insect's Alter Ego
› Locusts Plague Northern and Western Africa
› Locust Watch

Adam Voiland
NASA's Goddard Space Flight Center

For more information visit http://www.nasa.gov/images/content/388674main_portal2Huge.jpg

The Ups and Downs of Global Warming

According to the vast majority of climate scientists, the planet is heating up1. Scientists have concluded that this appears to be the result of increased human emissions of greenhouse gases, especially carbon dioxide, which trap heat near the surface of Earth. However, some information sources -- blogs, websites, media articles and other voices -- highlight that the planet has been cooling since a peak in global temperature in 1998. This cooling is only part of the picture, according to a recent study that has looked at the world's temperature record over the past century or more.

In their recently published research paper2 entitled "Is the climate warming or cooling?", David Easterling of the U.S. National Climate Data Center and Michael Wehner of Lawrence Berkeley National Laboratory show that naturally occurring periods of no warming or even slight cooling can easily be part of a longer-term pattern of global warming.

This may sound counter-intuitive at first sight, so let's take a closer look at the data. Figure 1 shows the change in the world's air temperature averaged over all the land and ocean between 1975 and 2008. The warming is obvious -- about 0.5° C (0.9° F) during that time. However, there are plenty of periods -- 1997 to 1985 and 1981 to 1989 (see insets, Figure 1), and 1998 to 2008 -- when no warming is seen, the most recent of which some global warming skeptics say is evidence that the world is actually cooling.

Figure 1: The world's surface air temperature change ("anomaly"), relative to the world's mean temperature of 58° F or 14.5° C, averaged over land and oceans from 1975 to 20082. Inset are two periods of no warming or cooling within this overall warming trend. Copyright 2009 American Geophysical Union. Reproduced/modified by permission of American Geophysical Union.

What's going on? To answer this question, Easterling and Wehner pored over global temperature records dating from 1901 to 2008 and also ran computer simulations of Earth's climate looking back into the past and forward into the future. They concluded that in a climate being warmed by man-made carbon emissions, "it is possible, and indeed likely, to have a period as long as a decade or two of 'cooling' or no warming superimposed on a longer-term warming trend."

Natural Fluctuations

These temperature plateaus, or cooling spells, can be attributed to natural climate variability, explains Josh Willis, a climate scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. and a recent recipient of the 2009 Presidential Early Career Award for Scientists and Engineers. "Natural variability refers to naturally-occurring fluctuations or events that change Earth's climate on time scales ranging from years to decades. Big volcanic eruptions, for instance, can cause cooling that lasts for several years. When a volcano erupts, it blasts dust into the upper atmosphere where it reflects sunlight and cools the planet, a bit like a natural umbrella." He goes on, "There are also all kinds of natural fluctuations that sometimes cause warming, sometimes cooling." Ocean changes, for instance, can have a big impact on the world's temperature. One example that Willis cites is the Pacific Decadal Oscillation, a pattern of warmer and cooler surface temperatures in the Pacific Ocean that can last between 10 and 30 years.

Another important example is El Niño, which is an abnormal warming of surface ocean waters in the eastern tropical Pacific that happens every three to eight years and can affect global temperatures for a year or two. Between 1997 and 1998, there was an unusually strong El Niño, and this caused 1998 to be one of the hottest years on record (Figure 1). When Easterling and Wehner dropped the 1998 temperature spike from the data altogether, and zoomed in on the readings from 1999 to 2008, they saw a strong warming trend over this period. But when the 1998 measurement is included in the data, it looks as if there is no overall warming between 1998 and 2008 at all.

The authors say that it is easy to "cherry-pick" a period to reinforce a particular point of view. "Claims that global warming is not occurring that are derived from a cooling observed over short time periods ignore natural variability and are misleading."

What you have to look at, says Willis, is the long-term temperature readings that have been collected over the past century -- which is exactly what Easterling and Wehner do in their study. Over that sort of time scale, global warming becomes apparent from observations of both our atmosphere and our ocean, which are intimately linked pieces of the climate puzzle.

Sea Change

Since around the time of the Industrial Revolution (the late 18th and early 19th centuries), Earth's atmosphere has warmed by a little less than 1° C (1.8° F) (Figure 2). In turn, the ocean has also risen by about 15 centimeters (6 inches) over the past 100 years -- for two reasons. First, when water warms up, it expands, in much the same way as a solid does when it heats up. As the volume of seawater increases, it causes sea level to rise. Second, global warming causes glaciers and ice sheets to melt, which adds more water to the world's ocean, again causing sea level to rise 4,5.

"If you look at the ocean data, there has been a very clear acceleration in sea level rise," explains Willis. "At the beginning of the last century, sea level was rising by less than 1 millimeter (0.04 inches) per year; mid-century it was 2 millimeters (0.08 inches) per year and now it's 3 millimeters (0.12 inches) per year. This is directly caused by the increasing temperature of the planet."

Big Picture

As Willis explains, global warming is a long-term process. "Despite the fact it's been warmer and cooler at different times in the last 10 years, there's no part of the last 10 years that isn't warmer than the temperatures we saw 100 years ago."

Assuming our greenhouse gas emissions continue at their present levels with little reduction, existing climate forecasts suggest that our planet will warm by about 4° C (7.2° F) by the end of the 21st century. Although scientists continue to study the nuances of Earth's climate, the link between carbon emissions, global warming and sea level rise over the past century is clear. Even if our global carbon emissions began to fall tomorrow, Earth would continue to warm for some time due to the inertia of the climate system6.

Figure 2: The world's average surface air temperature change ("anomaly") from 1880 to the present day3. Dotted black line shows the annual mean; the solid red line shows the five-year average. Green bars show estimates of the uncertainty in the measurements.

"In the next century it's definitely going to get warmer," Willis says. "You don't need a crystal ball or fancy climate model to say that. Just look at the sea level and temperature records from the past 100 years -- they're all going up." Likewise, Easterling and Wehner's work reminds us that understanding climate change -- one of the most important challenges we face today -- requires a long-term view. "Unlike people," says Willis, "the climate has a very long memory."

A Body of Evidence

In 2007, a scientific intergovernmental body called the Intergovernmental Panel on Climate Change (IPCC) released its Fourth Assessment Report on Climate Change, which summarizes our current understanding of climate change. The report took 6 years to produce, involved over 2500 scientific expert reviewers and more than 800 authors from over 130 countries.

Some of their key findings include:

  • The warming trend over the last 50 years (about 0.13° C or 0.23° F per decade) is nearly twice that for the last 100 years.
  • The average amount of water vapor in the atmosphere has increased since at least the 1980s over land and ocean. The increase is broadly consistent with the extra water vapor that warmer air can hold.
  • Since 1961, the average temperature of the global ocean down to depths of at least 3 km (1.9 miles) has increased. The ocean has been absorbing more than 80% of the heat added to the climate system, causing seawater to expand and contributing to sea level rise.
  • Global average sea level rose on average by 1.8 mm (0.07 inches) per year from 1961 to 2003. There is high confidence that the rate of observed sea level rise increased from the 19th to the 20th century.
  • Average arctic temperatures increased at almost twice the global average rate in the past 100 years.
  • Mountain glaciers and snow cover have declined on average in both hemispheres. Widespread decreases in glaciers and ice caps have contributed to sea level rise.
  • Long-term trends in the amount of precipitation have been observed over many large regions from 1900 to 2005.

For more information visit http://www.nasa.gov/topics/earth/features/upsDownsGlobalWarming.html

Ames Bioengineering Scientist Establishes GREEN Team

After earning his Ph.D. in Biological Oceanography at Scripps Institution of Oceanography, University of California at San Diego, Jonathan Trent spent six years in Europe at the Max Planck Institute for Biochemistry in Germany, the University of Copenhagen in Denmark, and the University of Paris at Orsay in France. He returned to the United States to work at the Boyer Center for Molecular Medicine at Yale Medical School for two years before establishing a biotechnology group at the Department of Energy's Argonne National Laboratory in Illinois.

Image of Jonathan Trent. Photo Credit: NASA Ames Research Center

In 1998, he moved to NASA Ames Research Center, where he established the Protein Nanotechnology Group. These researchers focus on building nanostructures using biomolecules from extremophiles-organisms adapted to extreme environments, such as high temperatures, high or low pH, ionizing radiation, or saturated salts. Using these robust biomolecules, and manipulating molecular recognition and self-assembly with genetic engineering, his team has built patterned nano-particle arrays for data storage and molecular scaffolds for enhancing enzyme activities.

In addition to working at NASA, Trent was appointed Adjunct Professor in the Dept. of Biomolecular Engineering at the University of California at Santa Cruz in 2004. Two years later, he was awarded the prestigious Nano50 award for Innovation in Nanotechnology, and was elected Fellow of the California Academy of Sciences. Since then, Trent has initiated Global Research into Energy and the Environment at NASA (GREEN) with support from Google. Among other projects, Trent and the GREEN team are developing systems for producing a sustainable, carbon-neutral feedstock for the biofuels of the future. Trent's recent research and inventions are focused on methods for obtaining alternative fuels, processing municipal wastewater, and economically producing freshwater by desalination. In April 2009, he organized and led an international conference in Denmark entitled: Wind, Sea, and Algae.

Ruth Marlaire
Ames Research Center, Moffett Field, Calif.
650.604.4709
ruth.marlaire@nasa.gov

For more information visit http://www.nasa.gov/centers/ames/research/2009/jonathan_trent.html

From Nothing, Something: One Layer at a Time

A group of engineers working on a novel manufacturing technique at NASA's Langley Research Center in Hampton, Va., have come up with a new twist on the popular old saying about dreaming and doing: "If you can slice it, we can build it."

That's because layers mean everything to the environmentally-friendly construction process called Electron Beam Freeform Fabrication, or EBF3150, and its operation sounds like something straight out of science fiction.

"You start with a drawing of the part you want to build, you push a button, and out comes the part," said Karen Taminger, the technology lead for the Virginia-based research project that is part of NASA's Fundamental Aeronautics Program.

She admits that, on the surface, EBF3 reminds many people of a Star Trek replicator in which, for example, Captain Picard announces out loud, "Tea, Earl Grey, hot." Then there is a brief hum, a flash of light and the stimulating drink appears from a nook in the wall.

Electron beam freeform fabrication process. Image credit: NASA

In reality, EBF3 works in a vacuum chamber, where an electron beam is focused on a constantly feeding source of metal, which is melted and then applied as called for by a drawing—one layer at a time—on top of a rotating surface until the part is complete.

While the options for using EBF3 are more limited than what science fiction allows, the potential for the process is no less out of this world, with promising relevance in aviation, spaceflight—even the medical community, Taminger said.

Commercial applications for EBF3 are already known and its potential already tested, Taminger said, noting it's possible that, within a few years, some aircraft will be flying with large structural parts made by this process.

To make EBF3 work there are two key requirements: A detailed three-dimensional drawing of the object to be created must be available, and the material the object is to be made from must be compatible for use with an electron beam.

First, the drawing is needed to break up the object into layers, with each cross-section used to guide the electron beam and source of metal in reproducing the object, building it up layer by layer.

"If you take a slice through a typical truss, you can see a couple of dots in each cross-section that move as you go from layer to layer," Taminger said. "When complete, you see those moving dots actually allowed you to build a diagonal brace into the truss."

A structural metal part fabricated from EBF3. Image credit: NASA

Second, the material must be compatible with the electron beam so that it can be heated by the stream of energy and briefly turned into liquid form, making aluminum an ideal material to be used, along with other metals.

In fact, the EBF3 can handle two different sources of metal—also called feed stock—at the same time, either by mixing them together into a unique alloy or embedding one material inside another.

The potential use for the latter could include embedding a strand of fiber optic glass inside an aluminum part, enabling the placement of sensors in areas that were impossible before, Taminger said.

While the EBF3 equipment tested on the ground is fairly large and heavy, a smaller version was created and successfully test flown on a NASA jet that is used to provide researchers with brief periods of weightlessness. The next step is to fly a demonstration of the hardware on the International Space Station, Taminger said.

Future lunar base crews could use EBF3 to manufacture spare parts as needed, rather than rely on a supply of parts launched from Earth. Astronauts might be able to mine feed stock from the lunar soil, or even recycle used landing craft stages by melting them.

But the immediate and greatest potential for the process is in the aviation industry where major structural segments of an airliner, or casings for a jet engine, could be manufactured for about $1,000 per pound less than conventional means, Taminger said.

Environmental savings also are made possible by deploying EBF3, she added.

Normally an aircraft builder might start with a 6,000-pound block of titanium and machine it down to a 300-pound part, leaving 5,700 pounds of material that needs to be recycled and using several thousand gallons of cutting fluid used in the process..

"With EBF3 you can build up the same part using only 350 pounds of titanium and machine away just 50 pounds to get the part into its final configuration," Taminger said. "And the EBF3 process uses much less electricity to create the same part."

While initial parts for the aviation industry will be simple shapes, replacing parts already designed, future parts designed from scratch with the EBF3 process in mind could lead to improvements in jet engine efficiency, fuel burn rate and component lifetime.

"There's a lot of power in being able to build up your part layer by layer because you can get internal cavities and complexities that are not possible with machining from a solid block of material," Taminger said.

Watch Karen Taminger's Electron Beam Freeform Fabrication Technical Seminar →

Jim Banke
NASA Aeronautics Research Mission Directorate

For more information visit http://www.nasa.gov/topics/aeronautics/features/electron_beam.html

NASA's Spitzer Spots Clump Of Swirling Planetary Material

PASADENA, Calif. -- Astronomers have witnessed odd behavior around a young star. Something, perhaps another star or a planet, appears to be pushing a clump of planet-forming material around. The observations, made with NASA's Spitzer Space Telescope, offer a rare look into the early stages of planet formation.

Planets form out of swirling disks of gas and dust. Spitzer observed infrared light coming from one such disk around a young star, called LRLL 31, over a period of five months. To the astronomers' surprise, the light varied in unexpected ways, and in as little time as one week. Planets take millions of years to form, so it's rare to see anything change on time scales we humans can perceive.

Astronomers using NASA's Spitzer Space Telescope found evidence that a companion to a star -- either another star or a planet -- could be pushing planetary material together, as illustrated here.

One possible explanation is that a close companion to the star -- either a star or a developing planet -- could be shoving planet-forming material together, causing its thickness to vary as it spins around the star.

"We don't know if planets have formed, or will form, but we are gaining a better understanding of the properties and dynamics of the fine dust that could either become, or indirectly shape, a planet," said James Muzerolle of the Space Telescope Science Institute, Baltimore, Md. Muzerolle is first author of a paper accepted for publication in the Astrophysical Journal Letters. "This is a unique, real-time glimpse into the lengthy process of building planets."

One theory of planet formation suggests that planets start out as dusty grains swirling around a star in a disk. They slowly bulk up in size, collecting more and more mass like sticky snow. As the planets get bigger and bigger, they carve out gaps in the dust, until a so-called transitional disk takes shape with a large doughnut-like hole at its center. Over time, this disk fades and a new type of disk emerges, made up of debris from collisions between planets, asteroids and comets. Ultimately, a more settled, mature solar system like our own forms.

Before Spitzer was launched in 2003, only a few transitional disks with gaps or holes were known. With Spitzer's improved infrared vision, dozens have now been found. The space telescope sensed the warm glow of the disks and indirectly mapped out their structures.

Muzerolle and his team set out to study a family of young stars, many with known transitional disks. The stars are about two to three million years old and about 1,000 light-years away, in the IC 348 star-forming region of the constellation Perseus. A few of the stars showed surprising hints of variations. The astronomers followed up on one, LRLL 31, studying the star over five months with all three of Spitzer's instruments.

The observations showed that light from the inner region of the star's disk changes every few weeks, and, in one instance, in only one week. "Transition disks are rare enough, so to see one with this type of variability is really exciting," said co-author Kevin Flaherty of the University of Arizona, Tucson.

Both the intensity and the wavelength of infrared light varied over time. For instance, when the amount of light seen at shorter wavelengths went up, the brightness at longer wavelengths went down, and vice versa.

Muzerolle and his team say that a companion to the star, circling in a gap in the system's disk, could explain the data. "A companion in the gap of an almost edge-on disk would periodically change the height of the inner disk rim as it circles around the star: a higher rim would emit more light at shorter wavelengths because it is larger and hot, but at the same time, the high rim would shadow the cool material of the outer disk, causing a decrease in the longer-wavelength light. A low rim would do the opposite. This is exactly what we observe in our data," said Elise Furlan, a co-author from NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The companion would have to be close in order to move the material around so fast -- about one-tenth the distance between Earth and the sun.

The astronomers plan to follow up with ground-based telescopes to see if a companion is tugging on the star hard enough to be perceived. Spitzer will also observe the system again in its "warm" mission to see if the changes are periodic, as would be expected with an orbiting companion. Spitzer ran out of coolant in May of this year, and is now operating at a slightly warmer temperature with two infrared channels still functioning.

"For astronomers, watching anything in real-time is exciting," said Muzerolle. "It's like we're biologists getting to watch cells grow in a petri dish, only our specimen is light-years away."

Other authors are Zoltan Balog, Max Planck Institute for Astronomy, Germany; Paul S. Smith and George Rieke, University of Arizona; Lori Allen, National Optical Astronomy Observatory, Tucson; Nuria Calvet, University of Michigan, Ann Arbor; Paola D'Alessio, National Autonomous University of Mexico; S. Thomas Megeath, University of Toledo, Ohio; August Muench, Harvard-Smithsonian Center for Astrophysics, Cambridge; William H. Sherry, National Solar Observatory, Tucson.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://www.spitzer.caltech.edu/spitzer and http://www.nasa.gov/spitzer.


Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

For more information visit http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20090923.html

Tuesday, September 22, 2009

Engineers to Practice on Webb Telescope Simulator

The huge assembly standing in Northrop Grumman Corporation’s high bay looks a lot like NASA's James Webb Space Telescope, but it’s a full-scale simulator of the space telescope’s key elements.

Engineers are using the simulator, consisting of the telescope’s primary backplane assembly and the sunshield’s integrated validation article, to develop the Webb Telescope’s hardware design. In addition, technicians are using it to gain experience handling large elements in advance of working with the actual hardware that will fly in space.

"Having a functioning demonstration article enables us to see how components, which were developed and tested individually, fit together as a whole system," said Martin Mohan, Webb Telescope program manager for Northrop Grumman Aerospace Systems sector. "The simulator is an effective risk reduction tool to help us validate design approaches early."

This photograph shows simulators of the James Webb Space Telescope's optical telescope element and the sunshield's integrated validation article, mated together in Northrop Grumman's high bay in Space Park. The simulators are used to check that the actual telescope components will fit properly when installed on the real thing. Credit: Northrop Grumman

John E. Decker, Deputy Associate Director for the Webb Telescope at NASA's Goddard Space Flight Center said, "Simulators are important for the development of any spacecraft, and they are absolutely critical for one with the size and complexity of the Webb Telescope. We have already learned many important lessons from this simulator, and we expect to learn many more."

The simulator is a key element in the company’s extensive test and verification program, which relies on incremental verification, testing, and the use of crosschecks throughout the Webb Telescope’s development. The goal is to ensure that the final end-to-end Observatory test is a confirmation of the expected results. Northrop Grumman’s approach emulates its highly successful Chandra X-ray Observatory test and verification program.

Northrop has conducted a variety of tests with the simulator, including checking the clearances between sunshield membranes and the telescope to evaluating membrane management hardware and simulating the backplane support structure’s alignment measurements for future testing.

Northrop Grumman is the prime contractor for the Webb Telescope, leading a design and development team under contract to NASA’s Goddard Space Flight Center. Ball Aerospace & Technologies Corp. is the principal optical subcontractor to Northrop Grumman for the JWST program. ATK builds the telescope backplane and ITT develops the complex cryogenic metrology for optical testing.

These Webb telescope simulators are full-scale representations of the optical telescope element and sunshield. Credit: Northrop Grumman

The James Webb Space Telescope is the next-generation premier space observatory, exploring deep space phenomena from distant galaxies to nearby planets and stars. The Webb Telescope will give scientists clues about the formation of the universe and the evolution of our own solar system, from the first light after the Big Bang to the formation of star systems capable of supporting life on planets like Earth. It is expected to launch in 2014. The telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.


Rob Gutro
NASA's Goddard Space Flight Center

For more information visit http://www.nasa.gov/topics/technology/features/webb_simulator.html

Astronaut James McDivitt, Others Inducted Into Aerospace Walk of Honor

Retired NASA Apollo program astronaut James McDivitt was inducted into the Aerospace Walk of Honor in Lancaster City, Calif. on Sept. 19, 2009. McDivitt, who commanded the Gemini IV mission in 1965 and the Apollo 9 mission in 1969, was one of five former test pilots and astronauts honored at the 20th induction ceremonies.

McDivitt was joined at the induction ceremony by retired NASA astronaut Gordon Fullerton, Apollo 17 commander Gene Cernan, NASA Dryden acting deputy director Gwen Young and Ron Smith, vice-mayor of the City of Lancaster, Calif. Cernan was the featured speaker during the ceremony.

Retired NASA Apollo program astronaut James McDivitt (right) is presented with a medal by Ron Smith, vice-mayor of the City of Lancaster, Calif., at the city’s Aerospace Walk of Honor induction ceremonies Sept. 19. Credit: NASA/Tom Tschida

Following the induction ceremony, McDivitt and the group wielded shovels in front of the Lancaster Performing Arts Center to plant a commemorative moon tree. The sycamore sapling is a second-generation descendant of sycamore trees that were germinated from seeds that were flown on the Apollo 14 moon mission in 1971. This moon tree joins dozens of other trees now growing at state capitols, university campuses, and other select locations across the nation.

McDivitt commanded the first American space walk mission during Gemini IV, and later during Apollo 9, he oversaw the first tests of the Lunar Module in orbit around Earth. Joining the Air Force in 1959, he started as a student test pilot. McDivitt quickly climbed through various positions and programs before being selected as an astronaut in 1962.

A graduate of the US Air Force Experimental Test Pilot School and member of the Society of Experimental Test Pilots, he has been honored with many awards highlighting his accomplishments, including two NASA Distinguished Service Medals, four Distinguished Flying Crosses, five Air Medals, the NASA Exceptional Service Medal, two Air Force Distinguished Service Medals, induction into the U.S. Astronaut Hall of Fame and the International Space Hall of Fame. McDivitt now joins the 93 other honorees in the Aerospace Walk of Honor.

Retired NASA astronaut Gordon Fullerton, Vice-Mayor of Lancaster City, Calif. Ron Smith, Apollo 17 commander Gene Cernan and NASA Dryden acting deputy director Gwen Young join James McDivitt (right) in wielding shovels at the planting of a commemorative moon tree after the induction ceremony. Credit: NASA/Tom Tschida

Established in 1990 by the Lancaster City Council, the Aerospace Walk of Honor runs along Lancaster Boulevard through the city where each inductee is memorialized with a granite pillar that recognizes the important contributions of each individual who 'soared above the rest.'

Lancaster City is near both Edwards Air Force Base and the NASA Dryden Flight Research Center making it a hotbed of aviation activity. Dryden Flight Research Center has been the home of NASA’s high performance aircraft research since it’s founding.

› Learn more about Moon Trees
› Learn more about the Aerospace Walk of Honor →

For more information visit http://www.nasa.gov/topics/people/features/mcdivitt_honored.html

New Vista of Milky Way Center Unveiled

A dramatic new vista of the center of the Milky Way galaxy from NASA's Chandra X-ray Observatory exposes new levels of the complexity and intrigue in the Galactic center. The mosaic of 88 Chandra pointings represents a freeze-frame of the spectacle of stellar evolution, from bright young stars to black holes, in a crowded, hostile environment dominated by a central, supermassive black hole.

Permeating the region is a diffuse haze of X-ray light from gas that has been heated to millions of degrees by winds from massive young stars -- which appear to form more frequently here than elsewhere in the Galaxy -- explosions of dying stars, and outflows powered by the supermassive black hole -- known as Sagittarius A* (Sgr A*). Data from Chandra and other X-ray telescopes suggest that giant X-ray flares from this black hole occurred about 50 and about 300 years earlier.



The area around Sgr A* also contains several mysterious X-ray filaments. Some of these likely represent huge magnetic structures interacting with streams of very energetic electrons produced by rapidly spinning neutron stars or perhaps by a gigantic analog of a solar flare.

Scattered throughout the region are thousands of point-like X-ray sources. These are produced by normal stars feeding material onto the compact, dense remains of stars that have reached the end of their evolutionary trail – white dwarfs, neutron stars and black holes.

Because X-rays penetrate the gas and dust that blocks optical light coming from the center of the galaxy, Chandra is a powerful tool for studying the Galactic Center. This image combines low energy X-rays (colored red), intermediate energy X-rays (green) and high energy X- rays (blue).

The image is being released at the beginning of the "Chandra's First Decade of Discovery" symposium being held in Boston, Mass. This four-day conference will celebrate the great science Chandra has uncovered in its first ten years of operations. To help commemorate this event, several of the astronauts who were onboard the Space Shuttle Columbia -- including Commander Eileen Collins -- that launched Chandra on July 23, 1999, will be in attendance.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

More information, including images and other multimedia, can be found at:

http://chandra.harvard.edu

and

http://chandra.nasa.gov

Credits: NASA/CXC/UMass/D. Wang et al.

For more information visit http://www.nasa.gov/mission_pages/chandra/multimedia/mosaic.html

Centaur is No Longer the Bridesmaid

Centaur was the unnamed companion to the Atlas V rocket when it launched from Cape Canaveral, Fla., on June 18, 2009. Their mission: lift NASA's Lunar Reconnaissance Orbiter (LRO) into its lunar orbit. Piggybacking a ride on the Centaur was also the Lunar Crater Observation and Sensing Satellite (LCROSS) that will impact the moon in October. But something is different about this mission for Centaur: instead of quietly parking itself in a long-duration orbit of the earth, Centaur accompanied the two spacecraft on their journey toward the moon. What is more, Centaur will be the center of attention for a few glorious minutes this October.

On Cape Canaveral Air Force Station's skid strip in Florida, the crane is being removed from the Centaur stage of the Atlas V rocket after placing the Centaur on the flatbed truck. The Centaur will be transported to the Astrotech facility in Titusville, Fla. Photo credit: NASA/Cory Huston

The main LCROSS mission objective is to confirm the presence or absence of water ice in a permanently shadowed crater near a lunar polar region. Mission scientists have determined that the best way to do this is to send one or more objects into the surface of the moon to generate a large plume that can be studied to determine the presence of water ice. LCROSS is a small spacecraft, and besides not being able to make a major impact, its primary role is to observe a larger impact. That creates the opportunity for Centaur to take center stage.

LCROSS, still attached to its Centaur upper stage rocket, executed a fly-by of the moon on June 23, 2009 and entered into an elongated Earth orbit to position LCROSS for impact on a lunar pole. On final approach, the shepherding spacecraft and Centaur will separate. The Centaur will act as a heavy impactor to create a debris plume that will rise above the lunar surface. Projected impact at the lunar South Pole is currently: Oct 9, 2009 at 7:30 a.m. EDT. The Centaur will excavate a crater approximately 20 meters wide and almost 3 meters deep. More than 250 metric tons of lunar dust will be lofted above the surface of the moon.

Following four minutes behind, the shepherding spacecraft will fly through the debris plume, collecting and relaying data back to Earth before impacting the lunar surface and creating a second debris plume.

On Cape Canaveral Air Force Station's Launch Complex 41, the crane lifts the Centaur upper stage into the Vertical Integration Facility for installation onto the Atlas V first stage, already in the tower. Photo credit: NASA/Jack Pfaller.

For almost 30 years, the NASA Glenn Research Center in Cleveland, Ohio, was responsible for the technical and cost and schedule management of the Centaur rocket. This program had an extraordinary operational success record. It was developed as an upper stage launch vehicle to be used with a first stage booster rocket, the Atlas rocket. Centaur's first mission objective was to send the unmanned Surveyor spacecraft to the Moon. Centaur has been used to boost satellites into orbit and propel probes into space. Mariner, Pioneer, Viking and Voyager spacecraft all got a boost from Centaur and provided invaluable data on these planets. Centaur also helped to revolutionize communication and expand the frontiers of space. In all, Glenn used Centaur for more than 100 unmanned launches. Centaur has quietly continued as the upper stage of the Atlas family of rockets from United Launch Alliance and the retired Titan IV from Lockheed Martin.

For each of its previous missions, Centaur quietly did its job and retreated out of the limelight. This time, Centaur is going out in style!

Go Centaur!

David DeFelice NASA Glenn Research Center

Note: NASA’s Ames Research Center, Moffett Field, Calif., is overseeing the development of the LCROSS mission with its spacecraft and integration partner, Northrop Grumman, Redondo Beach, Calif.

Read more about Centaur's history.


For more information visit http://www.nasa.gov/mission_pages/LCROSS/main/centaur_full_story.html

Desert Layover


Space shuttle Discovery is parked within the Mate-Demate Device gantry at NASA's Dryden Flight Research Cener prior to beginning turnaround processing for its ferry flight back to the Kennedy Space Center in Florida. Discoloration on Discovery's reinforced carbon-carbon nose cap gives evidence of the extreme heating it encountered during re-entry into the Earth' atmosphere prior to landing on Sept. 11, 2009, at Edwards Air Force Base in California. Image Credit: NASA/Tony Landis

For more information visit nasa.gov

Radar Map of Buried Mars Layers Matches Climate Cycles

PASADENA, Calif. -- New, three-dimensional imaging of Martian north-polar ice layers by a radar instrument on NASA's Mars Reconnaissance Orbiter is consistent with theoretical models of Martian climate swings during the past few million years.

Alignment of the layering patterns with the modeled climate cycles provides insight about how the layers accumulated. These ice-rich, layered deposits cover an area one-third larger than Texas and form a stack up to 2 kilometers (1.2 miles) thick atop a basal deposit with additional ice.

"Contrast in electrical properties between layers is what provides the reflectivity we observe with the radar," said Nathaniel Putzig of Southwest Research Institute, Boulder, Colo., a member of the science team for the Shallow Radar instrument on the orbiter. "The pattern of reflectivity tells us about the pattern of material variations within the layers."

A Radar instrument on NASA's Mars Reconnaissance Orbiter for mapping underground ice-rich layers of the north polar layered terrain on Mars.

Earlier radar observations indicated that the Martian north-polar layered deposits are mostly ice. Radar contrasts between different layers in the deposits are interpreted as differences in the concentration of rock material, in the form of dust, mixed with the ice. These deposits on Mars hold about one-third as much water as Earth's Greenland ice sheet.

Putzig and nine co-authors report findings from 358 radar observations in a paper accepted for publication by the journal Icarus and currently available online.

Their radar results provide a cross-sectional view of the north-polar layered deposits of Mars, showing that high-reflectivity zones, with multiple contrasting layers, alternate with more-homogenous zones of lower reflectivity. Patterns of how these two types of zones alternate can be correlated to models of how changes in Mars' tilt on its axis have produced changes in the planet's climate in the past 4 million years or so, but only if some possibilities for how the layers form are ruled out.

"We're not doing the climate modeling here; we are comparing others' modeling results to what we observe with the radar, and using that comparison to constrain the possible explanations for how the layers form," Putzig said.

The most recent 300,000 years of Martian history are a period of less dramatic swings in the planet's tilt than during the preceding 600,000 years. Since the top zone of the north-polar layered deposits -- the most recently deposited portion -- is strongly radar-reflective, the researchers propose that such sections of high-contrast layering correspond to periods of relatively small swings in the planet's tilt.

They also propose a mechanism for how those contrasting layers would form. The observed pattern does not fit well with an earlier interpretation that the dustier layers in those zones are formed during high-tilt periods when sunshine on the polar region sublimates some of the top layer's ice and concentrates the dust left behind. Rather, it fits an alternative interpretation that the dustier layers are simply deposited during periods when the atmosphere is dustier.

The new radar mapping of the extent and depth of five stacked units in the north-polar layered deposits reveals that the geographical center of ice deposition probably shifted by 400 kilometers (250 miles) or more at least once during the past few million years.

"The radar has been giving us spectacular results," said Jeffrey Plaut of NASA's Jet Propulsion Laboratory, Pasadena, Calif., a co-author of the paper. "We have mapped continuous underground layers in three dimensions across a vast area."

The Italian Space Agency operates the Shallow Radar instrument, which it provided for NASA's Mars Reconnaissance Orbiter. The orbiter has been studying Mars with six advanced instruments since 2006. It has returned more data from the planet than all other past and current missions to Mars combined. For more information about the mission, visit: http://www.nasa.gov/mro .

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.


Media contacts:
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

Maria Martinez 210-522-3305
Southwest Research Institute, San Antonio, Texas
maria.martinez@swri.org

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

For more information http://www.nasa.gov/mission_pages/MRO/news/mro-20090922.html